Replacing mayonnaise and margarine in diet could reduce risk of dementia death

14 August 2023 , 09:57

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Consuming olive oil regularly as part of a balanced diet could lessen the risk of dying from dementia (Image: Getty Images)

Olive oil has long been considered a super food which can help people lead healthier and longer lives when consumed as part of a balanced diet.

But now, a new study has suggested it could reduce the risk of dying from dementia by almost a third. The study was carried out by researchers at Harvard University. It comes at a time when countries around the world are facing rising rates of Alzheimer's and other forms of dementia as populations age.

Researchers have found using olive oil instead of fats such as margarine and commercial mayonnaise could reduce the risk of dying from dementia.. It is the first studying investigating the relationship between diet and dementia-related deaths.

Scientists analysed dietary questionnaires and death records from more than 90,000 US citizens over three decades. Of those, 4,749 had been recorded as dying from dementia.

Dementia is the name given to a range of conditions that affect memory and other mental abilities which interferes with day-to-day life. The conditions are caused by physical changes in the brain, with Alzheimer's being the most common.

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The study came at a time when populations around the world are facing rising rates of dementia (Getty Images/Image Source)

Researchers found people who consumed more than half a tablespoon of olive oil each day had a 28 per cent lower risk of dying from dementia compared with those who rarely or never ate olive oil. By replacing a single teaspoon of margarine or mayonnaise with olive oil each day, researchers found there was an associated lower risk of dying from dementia of eight to 14 per cent.

"Our study reinforces dietary guidelines recommending vegetable oils such as olive oil and suggests that these recommendations not only support heart health but potentially brain health, as well," said Anne-Julie Tessier, a postdoctoral fellow at the Harvard TH Chan School of Public Health.

"Opting for olive oil, a natural product, instead of fats such as margarine and commercial mayonnaise is a safe choice and may reduce the risk of fatal dementia."

Previous research found that people who used olive oil instead of processed or animal fats tended to have healthier diets and potentially better health outcomes. Other studies have linked higher olive oil intake with a lower risk of heart disease.

For this study, Ms Tessier found the relationship between olive oil and dementia mortality risk in this study was independent of overall diet quality - which could suggest olive oil has properties uniquely beneficial for brain health.

"Some antioxidant compounds in olive oil can cross the blood-brain barrier, potentially having a direct effect on the brain," she said. "It is also possible that olive oil has an indirect effect on brain health by benefiting cardiovascular health."

Research at this stage is observational, though, with Ms Tessier cautioning that it does not yet prove that olive oil is the cause of reduced risk of fatal dementia. More studies will be needed to confirm the effect, but researchers have said their study bolsters the evidence that using olive oil in place of other fats can help support a healthy diet.

Fiona Leishman